China will unveil its nuclear submarines this week at an international fleet review marking the 60th anniversary of its navy, official media reported yesterday.

The first known public appearance of the craft, off the northern port of Qingdao, will underscore the growing might of the People's Liberation Army navy and its attempts to build goodwill by increasing transparency.

The Chinese navy has gained prominence lately thanks to participation in the fleet battling pirates off the coast of Somalia - the first active mission outside the Pacific - and a confrontation with the US in the South China Sea last month.

The Chinese navy's commander, Admiral Wu Shengli, said the celebrations, which would include 21 ships from 14 foreign countries, would show his country as a force for "peace, harmony and co-operation" at sea, the Liberation Army Daily reported.

Wu told foreign commanders yesterday that navies needed to work together to confront transnational security threats such as piracy and terrorism. "Suspicions about China being a 'threat' to world security are mostly because of misunderstandings and lack of understandings about China," Wu's deputy, Vice-Admiral Ding Yiping, told the state news agency Xinhua. "The suspicions would disappear if foreign counterparts could visit the Chinese navy and know about the true situation."

He added: "It is not a secret that China has nuclear submarines, which are key to safeguarding our country's national security." Chinese media have speculated that the government will also use the celebrations to announce more details of its plan to build an aircraft carrier, which is seen by many as emblematic of its ambitions.

The United States and governments in the region are concerned about China's growing naval power, sea boundary disputes and rivalry for resources.

Admiral Gary Roughead, chief of US naval operations and a guest at the fleet parade, told reporters in Beijing he would use the visit to try to improve military relations, Reuters said. "We can all look at the types of ships and the types of airplanes and the numbers of airplanes - that's interesting and worthy of note," he said. "But it is how countries elect to use those capabilities, and what the purposes are that they see, and how they will use them and how they will interact with other navies. That's important and that's why this dialogue is under way."

He said Beijing had yet to specify the role an aircraft carrier would play.

"The fleet review and Somalia are being used by China to try to show that even as it projects its power it is not a threat to anyone," said Christian Le Miere, senior analyst for Asia at defence publication Jane's Country Risk. He said the PLA had sought to portray itself as transparent and a responsible partner, rebuilding military-to-military links with the US.

But he added that the US and Japan would be watching warily.

"The incident in the South China Sea was a very clear indication of the fears of both sides ... China is increasingly concerned by US monitoring of its activities and the US is increasingly concerned that the Chinese are developing longer-range blue-water capabilities," he said.

Last month the US accused Chinese boats, including a naval vessel, of harassing the USNS Impeccable in international waters, while China said the surveillance ship should not have been operating in its "exclusive economic zone". The stand-off took place 75 miles south of a major naval base.

The PLA navy has more than 225,000 personnel and is thought to have as many as 70 submarines, 10 of them nuclear-powered. It also has about 72 combat ships. But it is continuing to invest heavily in expanding and upgrading its fleet, with much of the PLA's hefty budget increases in recent years going to the navy.

Le Miere said China had focused on improving naval capabilities since the early 1990s as it became more confident about its land borders because of improved relations with Russia and the US, and land and air capabilities superior to those of its neighbours.

"We have seen new nuclear submarines, amphibious landing ships, fast attack craft and major surface weapons, and under the somewhat opaque 'Project 48' we are likely to see an aircraft carrier as well," he added.

• This article was amended on Friday 24 April 2009. Due to an editing error, the original version of this article said that Chinese nuclear submarines had gained prominence in recent battles with Somali pirates. This has been corrected.